Site visit: Leaf Tower
Commodore Contracting’s 60-storey tower project on Reem Island
There are meanings behind most names, and this is certainly true of the $272mn (AED1bn) Leaf Tower that is slowly taking shape on Abu Dhabi’s Reem Island.
Amer Shami, projects director of main contractor Commodore Contracting, says the plant-like shape of the 227.85m-tall building is no coincidence, as the structure means it offers panoramic views of the surrounding landscape.
And like a leaf atop a towering giant redwood, Shami claims that it is easily one of the tallest buildings in Reem Island.
The 60-storey, mixed-use tower has commercial, residential and retail elements. It has a built-up area of 250,000m².
“When we finished Sama Tower in 2009 that was the tallest building in Abu Dhabi, so we’re used to erecting tall buildings,” Shami says.
A unique aspect of the scheme is that, unlike most mixed-use towers, the residential units are located below the office blocks: in this case, from floors 8-30; and the offices floors from 32-56.
Each residential floor has six two-bedroom apartments and 12 one-bedroom apartments, while the office floors can accommodate up to 12 offices per floor.
Shami says the inverted layout has accelerated the construction process as it has allowed Commodore to start on the finishing works much earlier than would normally be possible.
“Most of the blockwork is in the residential section. That means I can start my finishing work very soon. I don’t have to wait to finish the structure.
“But you also have to be on the ball from day one in that case as everything is accelerated,” he says.
Before construction began on the residential floors, Shami insisted that three mock-ups of the apartments were made with the consent of the consultant, to ensure that every labourer knew exactly what was expected.
“I don’t leave any room for people to learn on the job from their mistakes. We want to get it right first time.”
“Two things are difficult in construction in my opinion. The start, and the close activity. After this, it’s just repeated work.”
The lift lobby on the eighth floor – the start of the residential section – has four lifts and is currently being finished through to complete fit-out stage. The office floors above, however, are being carried out only to shell and core, as specified by the tender.
“The client wants to leave these spaces for the companies that will rent them (to fit out),” says Shami.
One of the challenges of the tower’s Reem Island location was ensuring it contained adequate space for parking.
“In Reem Island, there are not many areas for parking outside of the building, so I have to ensure there is enough space for visitors. We have about 1,000 more parking spaces than the requirement for visitors.”
In total, the building has 2,764 parking spaces distributed across the two basement levels, ground floor and five podium floors. The podium also includes space for retail units and a restaurant.
Shami says that several modifications from the client pushed back the original handover date to July 2015.
Changes on the podium levels included a landscaped area on the sixth floor complete with swimming pool and terraces surrounded by vegetation. As a result, the building now has two pools as one was already in the original design as part of a spa and health club on the 57th floor.
There were also changes to the interior decoration for two tower entrances, with one entrance to be used for the tenants of the residential floors and the other for the offices, plus the addition of two escalators connecting the first basement with the ground floor.
In order to keep the project ticking over while modifications were being made, and also to ensure work ran in parallel, Shami split the site into three zones. This proved particularly useful with space so restricted as areas that were not in use at any given time were turned over for storage.
“One of the things with Reem Island is that you don’t have space for logistics. From your plot you only have one and-a-half metres you can use, so that was a big issue for us. I kept the building in zones. I would finish one zone here and delay another zone there. It all came down to how we planned the project in the early stages.”
Mobilisation began in October 2011 and raft foundation work started two months later with about 27,000m³ of concrete used.
Around 70% of the project is complete. The building core has been erected using the Grocon Lubeca System and the slabs and columns, following about three floors behind, put up using a Doka system. The target was to erect one floor every six days.
“The area of one floor is 2,500m². Some floors we actually finished in five days,” says Shami. “As for the core, it’s huge, about 350m³. One floor with the core, columns and everything is 1,100m³ of concrete, so that’s a great amount of concrete for a weekly pour.”
He added: “One of the issues here is the strength of concrete for the core. It’s 75 N/mm² (Newton per square millimetre), so it’s not easy to pump this concrete up to heights of nearly 230 metres.”
Shami says the choice of formwork was in part influenced by a desire to have the team become familiar with a range of different systems, as well as picking something that would get the job done.
“I always say there are a lot of good formwork firms out there but in this case, with the core for instance, we wanted to use Grocon, as I wanted my team to gain as much experience and flexibility with all types of systems. Plus we knew that Grocon was perfect for what we needed.”
The concrete structural works are currently on the critical path and expected to be completed by the end of April. At the same time, the façade cladding is in progress and will be finished by the end of December. Shami says the building is being clad with a unitised curtain wall system, which makes installation quick and easy.
Commodore currently has around 1,900 people on site but the project peak will only be reached in the next two months, when the nunber of workers on site will increased to between 2,300-2,500.
“We will be ramping up activities during this phase. More activities for MEP, for façades and aluminium, more joinery work; things like this. We will also be increasing the number of people working on the elevators as the shaft will be ready.”
As for the elevators, Shami says these were one of the long-lead items, along with the sanitaryware.
“Lots of people are surprised when I say sanitaryware. I know it will be installed by the end of the project but you need to know the drain point sleeve location, which is not similar for different types of sanitaryware.
He added: “I always let my team know the philosophy of a project and how we will start to ensure that we get ahead. I’ve been in construction since 1982 and I’m currently projects director on two other projects, so thinking ahead is the only way you can achieve success.”